#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>
#include <openssl/aes.h>
#include <unistd.h>
#include <string.h>

FILE *kept_ciphers, *key; 
uint8_t *ciphertext;

uint8_t rsbox[256] = {0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
  0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
  0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
  0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
  0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
  0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
  0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
  0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
  0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
  0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
  0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
  0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
  0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
  0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
  0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
  0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d };

bool loadTrace()
{
	return fread(ciphertext, sizeof(uint8_t), 16, kept_ciphers);
}

int main(){
	kept_ciphers = fopen("kept_ciphers.bin", "r");
	ciphertext = (uint8_t *) malloc(sizeof(uint8_t) * 16);
	int count[256] = {0};
	int i;

	//read in ciphers
	while(loadTrace() == true){
		//print cipher
		int j;
		for (j = 0; j < 16; j++){
        	printf("%02x ", (int)(ciphertext[j] & 0xff));
    	}
		printf("\n");
		
		// loop through cipher bytes
		int cypher_byte;
		for (i = 0; i < 16; i++) {
			cypher_byte = ciphertext[i];
			
			//loop through each key guess
			int k, s;
			for(k = 0; k < 256; k++) {
				s = rsbox[k ^ cypher_byte];
				if (s > 0 && s < 16)
					count[k]++; 
			}
		}
	}	
	
	// get 4 key bytes
	//for (i = 0; i < 256; i++)
	//	printf("index: %d count: %d\n", i, count[i]);
	int max = count[0];
	int key_byte1;
	for (i = 1; i < 256; i++) {
		if (count[i] > max) {
			max = count[i];
			key_byte1 = i;
		}
	}
	count[key_byte1] = 0;
	printf("Key byte1: %d\n", key_byte1);

	max = count[0];
	int key_byte2;
	for (i = 1; i < 256; i++) {
		if (count[i] > max) {
			max = count[i];
			key_byte2 = i;
		}
	}
	count[key_byte2] = 0;
	printf("Key byte2: %d\n", key_byte2);

	max = count[0];
	int key_byte3;
	for (i = 1; i < 256; i++) {
		if (count[i] > max) {
			max = count[i];
			key_byte3 = i;
		}
	}
	count[key_byte3] = 0;
	printf("Key byte3: %d\n", key_byte3);
	
	max = count[0];
	int key_byte4;
	for (i = 1; i < 256; i++) {
		if (count[i] > max) {
			max = count[i];
			key_byte4 = i;
		}
	}
	count[key_byte4] = 0;
	printf("Key byte4: %d\n", key_byte4);
}
